Search

In the process of grain storage, the use of low-temperature grain storage technology can effectively reduce grain losses during storage and ensure grain quality, which is of great significance for maintaining a stable grain supply. Radiative cooling materials, as a new energy-free cooling technology, achieve cooling by radiating heat in the form of electromagnetic waves into outer space. This approach can address issues associated with traditional cooling methods, such as high energy consumption and high chemical oxygen demand (COD) emissions, offering a green and environmentally friendly new approach to low-temperature grain storage. This paper explained the working principle of polymer-based radiative cooling materials and systematically introduced the composition and selection criteria of polymer-based radiative cooling systems. It also categorized and summarized polymer-based radiative cooling materials according to their structural characteristics. The existing problems with different structured radiative cooling materials, as well as future research directions, were also analyzed. This provides a certain research framework for applying radiative cooling materials to grain storage facilities to achieve low-temperature grain storage.

Objective To explore the efficacy and advantages of intracranial-intracranial bypass for the treatment of complex intracranial aneurysms. Methods A total of 9 patients with complex intracranial aneurysms who underwent intracranial-intracranial bypass in Xiangya Hospital of Central South University from February 2014 to May 2020 were included, and were treated with grafts bypass or reimplantation of recipient arteries. All cases underwent CTA or DSA to detect the patent of grafts, whether aneurysms were completely clipped or resected and aneurysms recurrence occurred during the follow-up. Modified Rankin Scale (mRS) was used to evaluate the neurological prognosis at discharge and during the follow - up. Results Radial artery (RA) or great saphenous vein (GSV) was used for interposition in 4 cases, and recipient arteries were used for reimplantation in 5 cases. Of 4 cases of interposition, the cavernous sinus seoment of internal carotid artery (ICA)-GSV-ICA bypass was adopted in one case, middle cerebral artery (MCA) M2-RA-M2 bypass in one case, anterior cerebral artery (ACA) A3-GSV-A3 bypass in one case, posterior cerebral artery (PCA) P2 -RA -P2 bypass in one case. Of 5 cases of reimplantation, MCA M2 inferior trunk was reimplanted to M2 superior trunk in one case, ACA A3 was reimplanted to contralateral A3 in 2 cases, the posterior inferior cerebellar artery (PICA) was reimplanted to the anterior inferior cerebellar artery (AICA) in 2 cases. CTA in 3 d postoperatively showed all cases grafts were patent and aneurysms disappeared. After 3 months of discharge, 2 were lost to follow-up. The other 7 cases kept the patency of grafts and no new aneurysms, and were constantly followed up, with an average follow-up time of 30.71 months, and mRS score was 1 or lower. Conclusions Intracranial - intracranial bypass can be applied for complex intracranial aneurysms that are difficult for conventional surgical treatment to solve. Compared with extracranial - intracranial bypass, its grafts are shorter and its hemodynamics features are more in line with physiological conditions.

The prismatic gas-cooled micro reactor core is composed of graphite prismatic blocks with gaps between them. The coolant passes through the gap to form flows that affect the flow and temperature distribution of the core. Conventionally, computational fluid dynamics methods have been used for prismatic gas-cooled reactor core analysis. However, they require considerable computational time and cost. For rapid and accurate calculation, in this study, a flow and heat transfer network analysis method is developed for evaluation of the core flow and temperature distribution. Finally, the calculated results of the flow heat transfer network analysis method are compared with the calculated results of computational fluid dynamics. The results show that the results of the flow heat transfer network analysis method are in good agreement with the results of computational fluid dynamics.

ObjectiveTo analyze the epidemiological characteristics of tetrodotoxin poisoning events in China from 2011 to 2020 and provide a scientific basis for precise measures to prevent and control tetrodotoxin poisoning.MethodsDescriptive epidemiological methods were used to analyze the epidemiological characteristics of tetrodotoxin poisoning incidents reported through the National Foodborne Disease Outbreak Monitoring System from 2011 to 2020.ResultsFrom 2011 to 2020， 92 cases of tetrodotoxin poisoning reports were received through the National Foodborne Disease Outbreak Monitoring System； 339 people were poisoned and 15 were dead， with a case fatality rate of 4.4%. Tetrodotoxin poisoning was mainly concentrated in the coastal areas of China. The food carriers of tetrodotoxin included pufferfish （71.7%， 66/92）， dried pufferfish （13.0%， 12/92）， Nassariidae （7.6%， 7/92）， horseshoe crabs （5.4%， 5/92）， and Acentrogobius nebulosus （2.2%， 2/92）. Each year， a high incidence of poisoning occurs from March to April.ConclusionTo effectively prevent and control tetrodotoxin poisoning， it is necessary to establish a method for detecting tetrodotoxins in biological samples， improve the ability to identify the pathogenic factors of tetrodotoxin poisoning， strengthen the supervision and popularization of science in the circulation process， and change the dietary habits of people who eat wild pufferfish.

ObjectiveTo obtain the occurrence time and regional distribution characteristics， place of occurrence， high-risk food and risk factors， the epidemiological characteristics of foodborne disease outbreaks caused by Vibrio parahaemolyticus from 2010 to 2020 in China’s Mainland was analyzed.MethodsThe data of foodborne disease outbreaks caused by Vibrio parahaemolyticus were collected from China disease outbreak surveillance system from 2010 to 2020 were analyzed statistically.ResultsFrom 2010 to 2020， a total of 1 772 outbreaks of foodborne diseases caused by Vibrio parahaemolyticus were reported， with a total of 27 212 cases， 5 944 hospitalized cases and 2 deaths. The peak time was from July to September. The incidence in developed areas （28.8 cases/million people） was higher than that in underdeveloped areas （8.2 cases/million people）， and the incidence in coastal areas （31.7 cases/million people） was higher than that in inland areas （9.2 cases/million people）. The main causes were aquatic food （61.2%） and meat （25.3%）. Hotels and restaurants accounted for 49.6% of the total. The main contamination links were incomplete cooking of aquatic food and raw and cooked cross-contamination of ready-to-eat meat and vegetable food.ConclusionIn order to reduce the risk of foodborne diseases caused by Vibrio parahaemolyticus， it is important to strengthen the supervision of processing and storage of aquatic food and meat in catering service places.

Abstract Traditional statistical methods (TSM) and machine learning (ML) methods have been widely used to separate the effects of emissions and meteorology on air pollutant concentrations, while their performance compared to the chemistry transport model has been less fully investigated. Using the Community Multiscale Air Quality Model (CMAQ) as a reference, a series of experiments was conducted to comprehensively investigate the performance of TSM (e.g., multiple linear regression and Kolmogorov–Zurbenko filter) and ML (e.g., random forest and extreme gradient boosting) approaches in quantifying the effects of emissions and meteorology on the trends of fine particulate matter (PM2.5) during 2013−2017. Model performance evaluation metrics suggested that the TSM and ML methods can explain the variations of PM2.5 with the highest performance from ML. The trends of PM2.5 showed insignificant differences (p > 0.05) for both the emission-related ( $${{\rm{PM}}}_{2.5}^{{\rm{EMI}}}$$ PM 2.5 EMI ) and meteorology-related components between TSM, ML, and CMAQ modeling results. $${{\rm{PM}}}_{2.5}^{{\rm{EMI}}}$$ PM 2.5 EMI estimated from ML showed the least difference to that from CMAQ. Considering the medium computing resources and low model biases, the ML method is recommended for weather normalization of PM2.5. Sensitivity analysis further suggested that the ML model with optimized hyperparameters and the exclusion of temporal variables in weather normalization can further produce reasonable results in emission-related trends of PM2.5.

ObjectiveTo trace Bacillus cereus （B. cereus） from foodborne disease outbreaks toidentify pathogens and cut off transmission.MethodsPulsed-field gel electrophoresis （PFGE） was performed. Furthermore， 12 isolates of B. cereus were subjected to PFGE. Subsequently， whole-genome sequencing （WGS） analysis was conducted on ten of these isolates. The WGS data were analyzed and assembled using BioNumerics software. Multilocus sequence typing （MLST）， virulence gene profiles， and single nucleotide polymorphisms （SNPs） were analyzed using assembled sequences.ResultsPFGE analysis classified the 12 B. cereus strains into nine pulsotypes. The three B. cereus isolates with the same PFGE pattern belonged to ST1435， and there were only three SNPs in the three ST1435 strains. The two B. cereus isolates with the same PFGE patterns were ST24 with one SNP between them， and the two ST24 isolates harbored hlbACD. These results indicate that the B. cereus isolates belonged to the same clone. The remaining three B. cereus strains also contained hlbACD.ConclusionFood-borne illness events caused by B. cereus are complex and are sources of contamination. Therefore， it will be necessary to strengthen the hygiene surveillance of food sources and workers and to pay more attention to cleaning and disinfecting environments and facilities， which will be important for preventing and controlling foodborne diseases.

The transition of graphic design from traditional print to mobile digital media has revolutionized the technology and the creative process. This evolution demands designers adapt their strategies to meet the challenges of smaller screens and varied user behaviors. This study explores how graphic design has transformed the mobile digital era, emphasizing the shift towards user interaction and visual communication efficiency. An empirical analysis of hundreds of designs reveals that innovative design methods significantly outperform traditional ones, increasing user engagement and communication effectiveness by 30% and 50%, respectively. The findings underscore graphic designers’ need to evolve their thinking and methodologies, enhancing interactivity and visual appeal to thrive in the mobile digital landscape.

Due to the implementation of air pollution control measures in China, air quality has significantly improved, although there are still additional issues to be addressed. This study used the long-term trends of air pollutants to discuss the achievements and challenges in further improving air quality in China. The Kolmogorov-Zurbenko (KZ) filter and multiple-linear regression (MLR) were used to quantify the meteorology-related and emission-related trends of air pollutants from 2014 to 2022 in China. The KZ filter analysis showed that PM2.5 decreased by 7.36 ± 2.92% yr−1, while daily maximum 8-h ozone (MDA8 O3) showed an increasing trend with 3.71 ± 2.89% yr−1 in China. The decrease in PM2.5 and increase in MDA8 O3 were primarily attributed to changes in emission, with the relative contribution of 85.8% and 86.0%, respectively. Meteorology variations, including increased ambient temperature, boundary layer height, and reduced relative humidity, also contributed to the reduction of PM2.5 and the enhancement of MDA8 O3. The emission-related trends of PM2.5 and MDA8 O3 exhibited continuous decrease and increase, respectively, from 2014 to 2022, while the variation rates slowed during 2018–2020 compared to that during 2014–2017, highlighting the challenges in further improving air quality, particularly in simultaneously reducing PM2.5 and O3. This study recommends reducing NH3 emissions from the agriculture sector in rural areas and transport emissions in urban areas to further decrease PM2.5 levels. Addressing O3 pollution requires the reduction of O3 precursor gases based on site-specific atmospheric chemistry considerations.

This paper mainly studies a high-precision correction method for warp knitting seamless images. The color factor conversion method is used to transform the gray level of the center point in the frequency domain. Then this paper proposes an image-denoising method based on an average way to improve image quality. The multichannel scalar channel is solved using the gradient domain method, and the fractional differential equations of two images are given. A structure tensor matrix is constructed to describe the geometric properties of images. The regional contrast of the image is calculated by using the characteristics of adjacent layers of pixels. The fusion of multiple images is based on the limitations of object functionality. This can make the texture structure of artistic color pictures more obvious. The experiment of color restoration shows that this method has a good interpretation effect. The color image processing technique has obtained an excellent restoration effect.

This study introduces Multi-Threshold Recurrence Rate Plots (MTRRP), a novel methodology for analyzing dynamic patterns in complex systems, such as those influenced by neurodegenerative diseases in brain activity. MTRRP characterizes how recurrence rates evolve with increasing recurrence thresholds. A key innovation of our approach, Recurrence Complexity, captures structural complexity by integrating local randomness and global structural features through the product of Recurrence Rate Gradient and Recurrence Hurst, both derived from MTRRP. We applied this technique to resting-state EEG data from patients diagnosed with Alzheimer’s Disease (AD), Frontotemporal Dementia (FTD), and age-matched healthy controls. The results revealed significantly higher recurrence complexity in the occipital areas of AD and FTD patients, particularly pronounced in the Alpha and Beta frequency bands. Furthermore, EEG features derived from MTRRP were evaluated using a Support Vector Machine with leave-one-out cross-validation, achieving a classification accuracy of 87.7%. These findings not only underscore the utility of MTRRP in detecting distinct neurophysiological patterns associated with neurodegenerative diseases but also highlight its broader applicability in time series analysis, providing a substantial tool for advancing medical diagnostics and research.

A conceptual design of a passive core cooling system (PCCS) was proposed in order to removal residual core heat during accident scenarios. Strong coupling feedback effect exists between natural convective heat transfer of the PCCS and the temperature distribution within the reactor core, which has a significant impact on the heat removal performance of the PCCS and the peak fuel temperature. An integral computational model dedicated to micro gas-cooled reactor, which includes both the PCCS and the reactor core, was developed. Comparisons of results predicted by this model and reference results of two benchmark problem, i.e. exercises of MHTGR and natural convection in a square cavity, show a satisfactory agreement, which thus validate the model. Thereafter, in order to explore the operational characteristics of the PCCS proposed in this work as well as the temperature response of the reactor core, and to assess its mitigative performance during accident scenario, this CFD model was then employed to analyze both the steady state under normal operation condition and the pressurized-loss-of-forced-cooling (PLOFC) accident. The calculation results show that the natural circulation of air is steady and regular during normal operation. The heat loss due to the PCCS is acceptably small, which will not lead to significant impact on the core temperature. During the PLOFC accident, the heat removal power of the PCCS is high in the early phase, whereas its performance gradually decreases as the temperature of the reactor vessel decreases in the long term. In general, the PCCS can effectively remove the residual core heat, thus maintaining the reactor integrity. Consequently, the integral CFD model created in this work can be applied to the design and the safety analysis of the PCCS for the micro gas-cooled reactor.

BackgroundMental health problems are common among men who have sex with men (MSM) living with HIV and may negatively affect medication adherence. Psychosocial interventions designed to address these urgent needs are scarce in China. Incorporating behavioral health theories into intervention development strengthens the effectiveness of these interventions. The absence of a robust theoretical basis for interventions may also present challenges to identify active intervention ingredients. ObjectiveThis study aims to systematically describe the development of a mobile health–based intervention for MSM recently diagnosed with HIV in China, including the theoretical basis for the content and the considerations for its technological delivery. MethodsWe used intervention mapping (IM) to guide overall intervention development, a behavioral intervention technology model for technological delivery design, and a human-centered design and cultural adaptation model for intervention tailoring throughout all steps of IM. ResultsThe dialectical behavior therapy (DBT)–informed intervention, Turning to Sunshine, comprised 3 components: app-based individual skills learning, group-based skills training, and on-demand phone coaching. The theoretical basis for the intervention content is based on the DBT model of emotions, which fits our conceptualization of the intervention user’s mental health needs. The intervention aims to help MSM recently diagnosed with HIV (1) survive moments of high emotional intensity and strong action urges, (2) change emotional expression to regulate emotions, and (3) reduce emotional vulnerability, as well as (4) augment community resources for mental health services. Technological delivery considerations included rationale of the medium, complexity, and esthetics of information delivery; data logs; data visualization; notifications; and passive data collection. ConclusionsThis study laid out the steps for the development of a DBT-informed mobile health intervention that integrated app-based individual learning, group-based skills training, and phone coaching. This intervention, Turning to Sunshine, aims to improve mental health outcomes for MSM newly diagnosed with HIV in China. The IM framework informed by human-centered design principles and cultural adaptation considerations offered a systematic approach to develop the current intervention and tailor it to the target intervention users. The behavioral intervention technology model facilitated the translation of behavioral intervention strategies into technological delivery components. The systematic development and reporting of the current intervention can serve as a guide for similar intervention studies. The content of the current intervention could be adapted for a broader population with similar emotional struggles to improve their mental health outcomes.

Biological aerosols are a special type of aerosols in the atmosphere, which have carcinogenic and teratogenic properties. Real-time detection and identification of biological aerosols is the prerequisite for biological warning and forecasting. The design of bipolar time-of-flight (TOF) mass analyzer is required to realize miniaturized vehicle bioaerosol mass spectrometer, with the mass range above 300 and mass spectrometry resolution at least 500. In this study, the exponential pulse delay elicitation technique was applied to the design of miniaturized TOF. Combined with SIMION 2020 software, the particle flight trajectory under the condition that the velocity dispersion was a Gaussian distribution with a peak value of 800 m/s and a spatial dispersion of 0.3 mm were simulated. The particle swarm optimization algorithm (PSO) was used to automatically optimize the voltage and delay time of the TOF. Under the optimized delay time of 130 ns, the resolution of more than 500 could be achieved in the full mass range even if the spatial dispersion and energy dispersion were in extreme cases, and mass deviation between different particles could be controlled within 0.4 u. The impact of normal square wave pulse delay extraction and exponential pulse delay extraction on the resolution of ions formed by a single particle was compared and analyzed. The results showed that exponential pulse delay extraction improves the resolution in the full mass range significantly better than square wave pulse. The effect of particle ionization position on mass spectrometry resolution was simulated when the particle was in the center of the spot and at the limit of 0.15 mm to left and right of the spot. The result showed that the resolution was different, but still better than 500. The detection of black carbon particles showed that the miniaturized TOF could obtain a resolution of more than 500 in the full mass range, which met the resolution requirements of the vehicle bioaerosol mass spectrometer. Although the flight length of the small TOF is 67% of that of SPAMS 0525, the resolution could reach more than 1.2-1.7 times due to the use of exponential pulse delay extraction technology. This study provides a design for a small time-of-flight mass analyzer, and indicates that there is still room for further reduction the size of time-of-flight mass analyzer for the miniaturized bioaerosol mass spectrometry. This study lays a research foundation for further reduction the volume of the subsequent bioaerosol mass spectrometer.

As the cornerstone of the development of the computational tool for the coupled neutronics and thermal-hydraulics analysis dedicated to the micro gas-cooled reactor, neutronic diffusion solver was developed in this work based on the generic 3D finite-element CFD code COMSOL Multiphysics by taking advantage of its equation-based modeling functionality “coefficient form PDE interface”. The steady-state and transient neutronic diffusion equations are solved using the eigenvalue solver and transient solver of this code, respectively. The neutronic diffusion solver developed in this work was firstly validated against two benchmark problems, i.e. 2D-TWIGL and 3D IAEA PWR problems respectively. The comparison of the calculation results of this solve with the reference values offered by the corresponding benchmark problems is satisfactory. Thereafter, this neutronic diffusion solve was applied to the micro gas-cooled reactor criticality analysis, with the group constants (including two-group and 25-group) generated by the Monte-Carlo code RMC. The calculation results of neutronic diffusion were also compared with the reference values derived by the Monte-Carlo transport calculations using the RMC code based on both continuous-energy-spectrum and multi-group methods. In general, the results obtained by solving both the two-group or 25-group neutronic diffusion equations, such as effective multiplication factor and three-dimension power distribution, can match well with the corresponding multi-group Monte-Carlo simulation. Whereas when comparing with the continuous-energy-spectrum MonteCarlo results, adopting the 25 energy groups is able to gain better accuracy in contrast to the two energy groups, indicating that the energy-group division has a significant impact on the neutronics for the micro gas-cooled reactor. The accuracy of prediction can be improved by adopting a more sophisticated energy group structure. However, the required computational source and time will dramatically increase with the number of energy groups.

ObjectiveTo analyze the epidemiological characteristics of foodborne disease outbreaks caused by takeaway in China’s Mainland from 2010 to 2020， and put forward relevant regulatory suggestions.MethodsThrough the National Foodborne Disease Outbreak Monitoring System， the data of foodborne disease outbreaks caused by takeaway in China’s Mainland from 2010 to 2020 were collected and analyzed， and descriptive epidemiological characteristics were performed.ResultsA total of 549 foodborne disease outbreaks caused by takeaway were reported in China’s Mainland （except Tibet Autonomous Region） from 2010 to 2020， resulting in 9 285 illnesses and 2 deaths. The largest number of outbreaks and illnesses was in the third quarter， accounting for 41.53% and 44.58% of the total respectively. Except the unknown pathogenic factors， the number of outbreaks and illnesses caused by microbial pathogenic factors were the highest， accounting for 39.16% and 60.26% of the total respectively. Except the unknown suspected food， the number of outbreaks and illnesses caused by mixed food and multiple food were higher， accounting for 21.86% and 15.12% of the outbreaks respectively， and accounting for 20.58% and 13.10% of the number of illnesses respectively. Except the unknown food source， the top 3 food source were school canteens， collective dining delivery units/central kitchens and fast food restaurants， the number of outbreaks accounted for 20.04%， 15.66% and 15.48% respectively， and the number of illnesses accounted for 35.30%， 17.52% and 10.57% respectively. Except the multiple factors and unknown factors， the number of outbreaks caused by improper storage were the highest accounting for 8.74%， and the number of illnesses caused by improper processing accounted for 7.74%.ConclusionMicrobial growth and reproduction due to improper storage and processing is the major cause of foodborne disease outbreaks caused by takeaway. It is suggested that the food safety supervision and administration departments should strengthen the whole process supervision and management of takeaway， establish and ensure catering services strictly abide by the good hygiene operations according to food raw in materials， production， transportation， distribution and other aspects， so as to effectively prevent and control the occurrence foodborne diseases.

A double potential well flat ion trap was designed as an ion accumulating and focusing device for multi-reflection time-of-flight mass analyzer. Two potential wells of the trap were severally used for accumulation of injected ions, controlled cooling and ejection of trapped ions, which had features to accumulate ions continuously and cool ion for almost one period. While a flat ion trap with only one potential well is a traditional and excellent ion accumulating and focusing device, which has an intermittent ion accumulation and an ion cooling around half period. Compared with the single potential well flat ion trap, the double potential well flat ion trap had better performance on ion accumulation and focusing in principle. Four steps to run the trap were simulated and researched by an ion optics simulator of SIMION 8.1. The first step was ion accumulation, ions were successively injected into the trap, and then stored and accumulated in the first potential well. The second step was ion transfer, the trapped ions were transferred from the first potential well to the second potential well. The third step was ion cooling, the trapped ions were confined in the second potential well, and were simultaneously cooled by collisions with 0.5 Pa He. The fourth step was ion ejection, the trapped ions were ejected from the trap and focused into the next device. Ion optics simulations indicated that the trap had a period from 1 ms to above 10 ms, a total ion transmission efficiency of 83%, and an ion flux of at most 1.6×106 ions. In addition, ion packets ejected from the trap had thermalized with radial diameters of 1.0 and 1.0 mm, angular standard deviations of 24 mrad and 16 mrad, and an energy standard deviation of 15 eV. This trap can be coupled with and provide high-flux and full-focusing ion packets for multi-reflection time-of-flight mass analyzers, due to an excellent suitability between the operation of the analyzer and the period, the ion transmission efficiency, the ion flux, and ejected ion packets of the trap.

As the economy continues to advance, and the populace's demand for material well-being grows, urban areas are witnessing an increasing need for electricity supply. Substations, playing a pivotal role in the power industry, are proliferating in terms of both quantity and construction scale. Reinforced concrete substation buildings are a common infrastructure that provides a suitable physical environment for the operation of power equipment. A thorough examination and analysis conducted through on-site investigations have unveiled deficiencies in the low-carbon design and operation of substation buildings, resulting in energy wastage and extra carbon emissions. Consequently, this study endeavors to introduce a method for calculating carbon emissions during the operational phase of reinforced concrete structure substations. It also presents corresponding strategies for low-carbon design and operation. These strategies encompass low-carbon design principles for the building envelope structure, the utilization of renewable energy, low-carbon design considerations for artificial lighting, and the implementation of intelligent environmental control systems. The strategies proposed in this research provide valuable ideas for making the power and construction industries more environmentally friendly and energy-efficient.

Analyses of representative accident scenarios are imperative to assess and evaluate the inherent safety features of a prismatic modular high temperature gascooled reactor (HTGR). The accident progression of a HTGR is typically characterized by the coupling of multiphysics phenomena. However, computational codes available for the HTGR accident analyses are still relatively rare at present, especially those dedicated to the prismatictype core design. In addition, many of these codes are either lumpedparameter that cannot give the detailed threedimension (3D) distributions of key variables (e.g. fuel temperature), or are incapable of capturing the coupling of major phenomena. As a consequence, a generic CFD code, i.e. COMSOL multiphysics, was employed in this work to create a detailed 3D geometry representing the reactor, including fuel assemblies containing fuel and coolant channels, graphite moderator blocks, side reflector as well as the reactor pressure vessel. Specifically, the passive residual heat removal system (RCCS) was simply treated as a convective boundary condition due to the lack of detailed design scheme right now. A point kinetics module was prepared in this work using C++ language to account for the transient neutron kinetics. The Gear algorithm was applied to numerically solve the system of equations of the point kinetics, given that the stiffness is relatively large. The C++ was then compiled into dynamic link library (DLL), which was accessed by the COMSOL simulation in the form of an external function, with the fuel and moderator temperatures evaluated by COMSOL as input arguments. The steady state under normal operation condition was first calculated, which served as the initial condition for the subsequent transient analyses for three selected typical accidents, including pressurized loss of forced cooling (PLOFC), PLOFC without scram (PLOFC+ATWS), and reactivity insertion without scram (RIA+ATWS) accidents. Finally, sensitivity analysis was carried out on the effect of radiative emissivity between reactor pressure wall and RCCS. The simulation results show that the peak fuel temperature throughout the whole accident progression is remained far below its upper limit value (1 620 ℃) with a considerably large margin, implying that the integrity of fuel assemblies can be successfully guaranteed under the accident scenarios concerned in the present work. Moreover, enhancement of the RCCS heat removal capacity can significantly relief the accident consequence for PLOFC accident but lead to an inverse trend for ATWS accident, which underlines the importance of further comprehensive analysis and modeling validation. To conclude, the computational model developed in this work along with the derived results can serve as the starting point for future development of the accident analysis tool, which is applicable for the incoming indepth safety analysis and assessment works.

Concentrating on the problem of massive energy loss in the compressor, expansion valve, and the other components present in the high-temperature heat pump system under extensive temperature lift, the dual-flash compound circulation system is proposed and the thermodynamic model of the dual-flash compound circulation system was established. The article combines the multivariate simulated annealing algorithm, utilizes the system COP as the optimization goal, and completes the calculation of the thermodynamic parameters in the steady-state of the system that is based on satisfying the conditions of the system process. Using R245fa as the refrigerant, the condensation temperature is set within the range of 110°C–140°C for the model calculation. The results show that, compared to the traditional two-stage compression system under the same environment, the COP of the dual-flash compound circulation system can be increased up to 5.71%–12.13%, and the exergy efficiency can be increased by 5.11%–10.71%, respectively. Besides, steam production per unit refrigerant is also increased by 3.79%–5.14%. Finally, the feasibility of the theoretical model is verified by simulation, and it is concluded that the dual-flash compound circulation system has better steam production performance at the extensive temperature lift and the elevated condensation temperature.

ObjectiveTo understand the microbial contamination status of retail Chinese salads in Huzhou， and conduct a fast quantitative risk assessment to provide reference for foodborne disease prevention and control.MethodsIn 2019 and 2020， 461 samples of retail Chinese salads were randomly collected and detected for E.coli， Salmonella， Listeria monocytogenes， and B.cereus. According to the relevant standards， the status of microbial contamination was evaluated， and the health risk was preliminarily evaluated by sQMRA tool.ResultsThe unqualified rate of E.coli in retail Chinese salads was the highest （48.94%， 46/94）， and the average concentration was 104.34 CFU/g， which was mainly in the circulation links of farmer’s markets and online stores （P = 0.004）. The detection rates of Listeria monocytogenes， S.aureus， Salmonella and B.cereus were 9.54% （44/461）， 5.21% （24/461）， 1.30% （6/461） and 1.06% （1/94）， respectively. The unqualified rates of S.aureus（≥104 CFU/g） and B.cereus （≥105 CFU/g） were zero. The estimated annual incidence of four food borne pathogens was 2 208 cases， the estimated probability was 7.21 × 10-4， and the risk level was medium.ConclusionThe sanitary quality of retail Chinese salads in Huzhou City is not optimistic， E.coli contamination is the most serious. The contamination of four major food borne pathogens can lead to certain health risks. And further surveillance， assessment and management are needed．

Abstract Background HIV epidemic among men who have sex with men (MSM) remains a major public health concern in China. Despite a growing body of research on transgender women worldwide, little is known about Chinese transgender women within MSM. We sought to estimate HIV incidence and distinguish risk factors of HIV acquisition among them from that among cisgener (non-transgender) MSM (cis-MSM). Methods We conducted an open cohort study among Chinese MSM, including those who were identified as transgender in Shanghai and Tianjin. Participants were initially recruited by local community-based organizations from January to June, 2016, and were followed up approximately every 6 months until June 2018. At each visit, a structured questionnaire was used to gather information on demographics, sexual risk behaviors, and HIV status. HIV incidence was calculated as the number of seroconversions divided by total number of person-years of follow-up among HIV-negatives at baseline. Risk factors of HIV acquisition were assessed by univariate and multivariate Cox regression models with time-dependent variables. Results A total of 1056 participants contributed 1260.53 person-years (PYs) of follow-up, 33 HIV seroconversions occurred during the follow-up period, yielding an estimated HIV incidence of 2.62 (95% CI 1.80–3.68) per 100 PYs. HIV incidence among transgender women was 4.42 per 100 PYs, which was significantly higher than that of 1.35 per 100 PYs among cis-MSM, demonstrating a threefold higher odds of HIV infection than cis-MSM. For transgender women, those lived locally ≤ 2 years (adjusted hazard ratio [aHR] = 1.76, 95% CI 1.13–2.76) and unprotected anal sex last time (aHR = 4.22, 95% CI 1.82–9.79) were more likely to acquire HIV. For cis-MSM, factors associated with HIV acquisition were frequency of anal sex ≥ 3 times in past one month (aHR = 4.19, 95% CI 1.06–16.47) and unprotected anal sex last time (aHR = 5.33, 95% CI 1.52–18.73). Conclusions Compared to cis-MSM, transgender women were at higher risk of HIV acquisition, highlighting an urgent need of tailored prevention. Future HIV program should consider to include them to ensure that this population in China are not left behind. Graphical abstract

Light-absorbing organic carbon (OC), sometimes known as Brown Carbon (BrC), has been recognized as an important fraction of carbonaceous aerosols substantially affecting radiative forcing. This study firstly developed a bottom-up estimate of global primary BrC, and discussed its spatiotemporal distribution and source contributions from 1960 to 2010. The global total primary BrC emission from both natural and anthropogenic sources in 2010 was 7.26 (5.98–8.93 as an interquartile range) Tg, with 43.5% from anthropogenic sources. High primary BrC emissions were in regions such as Africa, South America, South and East Asia with natural sources (wild fires and deforestation) contributing over 70% in the former two regions, while in East Asia, anthropogenic sources, especially residential solid fuel combustion, accounted for over 80% of the regional total BrC emissions. Globally, the historical trend was mainly driven by anthropogenic sources, which increased from 1960 to 1990 and then started to decline. Residential emissions significantly impacted on emissions and temporal trends that varied by region. In South and Southeast Asia, the emissions increased obviously due to population growth and a slow transition from solid fuels to clean modern energies in the residential sector. It is estimated that in primary OC, the global average was about 20% BrC, but this ratio varied from 13% to 47%, depending on sector and region. In areas with high residential solid fuel combustion emissions, the ratio was generally twice the value in other areas. Uncertainties in the work are associated with the concept of BrC and measurement technologies, pointing to the need for more studies on BrC analysis and quantification in both emissions and the air.

ObjectiveThe purpose of this meta-analysis is to systematically assess the effects of psychological intervention on empathy fatigue among nursing staff.MethodFive electronic databases are searched separately from their establishment to April 8th, 2022. The research team independently performs paper selection, quality assessment, data extraction and analysis for all included studies. PRISMA guidelines are used to report this meta-analysis.ResultsA total of seven randomized controlled trials (RCTs) covering 513 nursing staff are included. The meta-analysis results show that the empathy fatigue score (SMD = −0.22, 95% CI: −0.42~−0.02, P = 0.03) and burnout (SMD = −0.37, 95% CI: −0.56~−0.19, P < 0.001) are lower than the control group. The empathy satisfaction score of the psychological intervention group is higher than that of the control group (SMD = 0.45, 95% CI: 0.27–0.63, P < 0.001). The differences are statistically significant (P < 0.05). Subgroup analysis finds significant heterogeneity in the impact of different departments on psychological intervention at ≥6 weeks (I2 = 71%, P = 0.01) and

Objective To summarize the key points of neuroendoscopic transcranial resection for cerebellopontine angle (CPA) tumors. Methods Twenty⁃eight patients with CPA tumors diagnosed and treated in Xiangya Hospital Central South University from January 2019 to December 2020 were included, and all of them underwent neuroendoscopic transcranial surgery to remove CPA tumors. Results All the 28 patients were successfully treated with neuroendoscopic transcranial resection of tumors in CPA region, and the tumors were totally removed. After operation, 9 cases of acoustic neuroma, 8 cases of meningioma, 9 cases of cholesteatoma, one case of hemangioblastoma, and one case of trigeminal neurinoma were confirmed by postoperative pathology. Postoperative facial nerve function was grade Ⅲ in 3 cases, grade Ⅱ in 6 cases, and grade Ⅰ in 19 cases. One patient had no obvious recovery of auditory nerve function injury, and 2 patients had dizziness, vertigo and nausea after operation. No complications such as cerebrospinal fluid leakage, meningitis and incision infection occurred, and no death occurred. At 3 months of follow ⁃ up, no tumor recurrence was seen on MRI, and no new neurological symptoms occurred. Conclusions Neuroendoscopic transcranial resection of CPA tumors has many advantages, but also has some shortcomings, and has a good development in the future.

Abstract The result of Aethalometer model to black carbon (BC) source apportionment is highly determined by the absorption Ångström exponent (α) of aerosols from fossil fuel combustion (α ff) and wood burning (α wb). A method using hourly measured potassium to calculate the α ff and α wb values was developed in this study. Results showed that the optimal α ff and α wb were 1.09 and 1.79 for the whole dataset. The optimal α values in the diurnal resolution were also calculated with α ff and α wb varied in 1.02 –1.19 and 1.71–1.90, respectively. Using the dynamic α values, the Pearson correlation coefficient between BC and potassium from wood burning substantially improved compared to the results derived from the fixed α values. The method developed in this study is expected to provide more reasonable BC source identification results, which are helpful for air quality, climate, and human health modeling studies.

Abstract The less improvement of ambient visibility suspects the government’s efforts on alleviating PM2.5 pollution. The COVID-19 lockdown reduced PM2.5 and increased visibility in Wuhan. Compared to pre-lockdown period, the PM2.5 concentration decreased by 39.0 μg m−3, dominated by NH4NO3 mass reduction (24.8 μg m−3) during lockdown period. The PM2.5 threshold corresponding to visibility of 10 km (PTV10) varied in 54–175 μg m−3 and an hourly PM2.5 of 54 μg m−3 was recommended to prevent haze occurrence. The lockdown measures elevated PTV10 by 9–58 μg m−3 as the decreases in PM2.5 mass scattering efficiency and optical hygroscopicity. The visibility increased by 107%, resulted from NH4NO3 extinction reduction. The NH4NO3 mass reduction weakened its mutual promotion with aerosol water and increased PM2.5 deliquescence humidity. Controlling TNO3 (HNO3 + NO3 −) was more effective to reduce PM2.5 and improve visibility than NH x (NH3 + NH4 +) unless the NH x reduction exceeded 11.7–17.5 μg m−3.

In order to overcome the short battery life and poor long-distance maneuverability of Unmanned Aerial Vehicle (UAV) in power inspection operations, some provincial and municipal power companies promote a new mode of “UAV and operating vehicle (OV)” collaborative power inspection. This paper investigates into the actual problems in the cooperative inspection operations of the OV and multi-UAVs, and proposes a model of task allocation for the cooperative inspections of the OV and multi-UAVs, which includes four sub-problems: the division of a single operation circle, the location of parking spots, multi-UAVs task allocation, and the path planning of OV. The proposed model is solved by using improved K-means algorithm and genetic algorithm, and case analysis is carried out. The calculation results show that the model of task allocation for cooperative inspections proposed in this paper is practical and feasible, which can provide theoretical guidance for actual power inspections.

Residential coal combustion (RCC) emission exhibited obvious daily variation, while no real-time estimation of air pollutants from RCC has been reported, as the shortages of corresponding activity dataset and emission factors with high time resolution. A real-time monitoring platform for RCC emission was established. Hourly emission factors of 18 typed of TEs from eleven kinds of chunk coals and nine kinds of honeycomb coals burning in China were obtained. The monthly and hourly coal consumption amounts were calculated with reference and our field survey. Then the hourly TEs emission inventories from RCC were established in China. GEOS-Chem and Risk Quotients Models were utilized to map the spatialized health risks of hazardous elements, including the gridded hazard index and carcinogenic risk. The result indicated that the EFs of TEs would be underestimated if the tests only consider flaming conditions. Cu, K, Ca, Zn, and Co were the top five elements from RCC, with corresponding emission amounts as 1397.7, 1054.0, 676.0, 623.5 and 420 tons in 2017, respectively. K, Ti, Fe, Sn, and Sb showed hourly peak values under flaming dominated periods, accounting for 48.2%, 45.9%, 31.8%, 42.8%, and 33.8% of their daily emissions. Other elements (e.g., V, Co, As, Hg and Pb) exhibited higher emissions under smoldering dominated period in nighttime, accounting for 22.2%, 32.9%, 27.6%, 34.7%, and 28.4% of their daily emissions. TEs emission from RCC closely follows the habits of human daily cooking and heating activity. The national HI were lower than the acceptable level (HI ≤ 1) except Sichuan Province (up to 1.2). Higher carcinogenic risks (≥1 × 10-6) occurred in parts of Sichuan, Shanxi, Hunan and Hubei, which were up to 2.0 × 10-5. The high-resolution TEs emission inventories could be useful for future modeling works on the formation and evolution of air pollution and are helpful for human exposure assessment.

Purpose:Neuroimaging elucidations have shown structural and functional brain alterations in HIV-infected (HIV+) individuals when compared to HIV-negative (HIV–) controls. However, HIV− groups used in previous studies were not specifically considered for sexual orientation, which also affects the brain structures and functions. The current study aimed to characterize the brain alterations associated with HIV infection while controlling for sexual orientation.Methods:Forty-three HIV+ and 40 HIV– homosexual men (HoM) were recruited and underwent resting-state MRI scanning. Group differences in gray matter volume (GMV) were assessed using a voxel-based morphometry analysis. Brain regions with the altered GMV in the HIV+ HoM group were then taken as regions of interest in a seed-based analysis to identify altered functional connectivity. Furthermore, the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity values were compared between the two groups to evaluate the HIV-associated functional abnormalities in local brain regions.Results:HIV+ HoM showed significantly increased GMV in the bilateral parahippocampal gyrus and amygdala, and decreased GMV in the right inferior cerebellum, compared with the HIV– HoM. The brain regions with increased GMV were hyper-connected with the left superior cerebellum, right lingual gyrus, and left precuneus in the HIV+ HoM. Moreover, the ALFF values of the right fusiform gyrus, and left parahippocampal gyrus were increased in the HIV+ HoM. The regional homogeneity values of the right anterior cingulate and paracingulate gyri, and left superior cerebellum were decreased in the HIV+ HoM.Conclusion:When the study population was restricted to HoM, HIV+ individuals exhibited structural alterations in the limbic system and cerebellum, and functional abnormalities in the limbic, cerebellum, and visual network. These findings complement the existing knowledge on the HIV-associated neurocognitive impairment from the previous neuroimaging studies by controlling for the potential confounding factor, sexual orientation. Future studies on brain alternations with the exclusion of related factors like sexual orientation are needed to understand the impact of HIV infection on neurocognitive function more accurately.

Isothermal compression tests were carried out on a Gleeble-3500D thermal simulation machine. The hot compression deformation behavior of a new hot-extruded Ni-Co-Cr-based powder metallurgy(P/M) superalloy at the temperatures from 1020℃ to 1110℃ with the strain rates from 10-3 s-1 to 1 s-1was systematically investigated. The flow stress curves were corrected by friction. Using the friction-corrected data, the constitutive equation for hot compression of the alloy and the flow stress model considering the strain compensation were established, respectively. At the same time, the hot processing map was built, and the hot deformation parameters of the alloy were optimized by combining with the analysis of the microstructure. The results show that apparently dynamic recrystallization occurs in the process of hot compression of the alloy, and the flow stress decreases with the decrease of strain rate or the increase of deformation temperature. The predicted values obtained from the developed flow stress model considering the strain compensation agree well with the experimentally friction-corrected data. According to the hot processing map and microstructural analysis, the reasonable hot working parameters of the alloy were suggested to be at the deformation temperatures of about 1076-1103℃ and the strain rates of about 10-3-10-2.77s-1.

Geometry and mechanical characteristics of joints are key factors affecting the shear behaviors and fracture patterns of jointed rock mass. Using 3D printing technique, experimental jointed rock specimens containing rough joints with varied joint roughness coefficient (JRC), different types of geometrical joints, and fractrues network were established respectively. Then direct shear tests were conducted on the jointed rock models to study the shear strength and failure patterns. The results show that the values of shear strength of jointed rock models fluctuate greatly with varied JRC curves. The peak shear displacement decreases with increasing amplitude of fluctuation. The lowest and highest values of shear strength are found in plane and rectangular joints, respectively. Moreover, the value of shear strength of sinusoidal type is found similar to that of triangular type. The shear strength of the 3D-printed fractured rock specimens are apparently lower than that of the intact rock specimens. When considering joint roughness, the peak shear stresses of rough discrete fractures network (RDFN) models are higher than those of the discrete fractures network (DFN) models. The solid rock specimens exhibit typical brittle shear failure. The fracture patterns of DFN model and RDFN model are relatively complex and the main shear fractures are found along the shear direction. Meanwhile, certain intersection points between joints and certain surfaces have significant influence over the shear failures. The present work provides references for the application of 3D printing technique in studying the shear behaviors of fractured rock masses.

Abstract Background In China, addressing disparities in the HIV epidemic among men who have sex with men (MSM) requires targeted efforts to increase their engagement and retention in prevention. In an effort to advance MSM-friendly HIV services within China, and informed by community-based partnerships, we tested whether MSM who have ever versus never disclosed their same-sex behavior to healthcare providers (HCP) differ in sociodemographic and behavioral characteristics as well as the qualities of sexual health services each group would prefer to access. Methods We conducted a cross-sectional survey among HIV-negative MSM who went to MSM-focused voluntary counseling and testing clinics in four cities in China. The survey was anonymous and collected information on sociodemographic characteristics, testing behaviors, sexual-health related behavior, and sexual health service model preferences. Results Of 357 respondents, 68.1% participants had ever disclosed same-sex behavior to HCPs when seeking advice for sexual health. Younger age (aOR = 1.04; 95% CI: 1.01-1.08), and worry of HIV acquisition (aOR = 1.39; 95% CI: 1.05–1.84) were associated with higher odds of past disclosure. The availability of comprehensive sexual health services was one of the most valued characteristics of the ideal sexual health clinic. Those who ever disclosed and never disclosed differed significantly in their ranking of the importance of three out of ten dimensions: sexual health counseling services available (M = 3.99 vs. M = 3.65, p = .002), gay identity support available (M = 3.91 vs. M = 3.62, p = .016) and clinic collaborates with a gay CBO (M = 3.81 vs. M = 3.56, p = .036). Conclusions Our hypothesis that MSM who had disclosed versus never disclosed same-sex behavior would differ in the value they placed on different dimensions of sexual health service was partially borne out. As health authorities in China decide on implementation models for pre-exposure prophylaxis (PrEP) delivery and specifically within which institutions to integrate PrEP services, the preferences of target populations should be considered to develop comprehensive, patient-centric and LGBT-friendly services.

The aim of this study was to evaluate the role of miR-181a-5p in sepsis, and to further explore the molecular mechanism. RAW 264.7 cells were stimulated with 1 μg/ml LPS for 4 hours. Firstly, qRT-PCR and ELISA was adopted to evaluate the expression of miR-181a-5p and p ro-inflammatory cytokines in RAW 264.7 macrophages a fter LPS stimulation. Results showed that pro-inflammatory cytokines and miR-181a-5p were significantly increased after LPS treatment. Then, we identified that sirtuin-1 (SIRT1) was a direct target of miR-181a-5p and it was down-regulated in LPS treated RAW264.7 macrophages. Furthermore, the data suggested that the miR-181a-5p inhibitor significantly inhibited LPS enhanced inflammatory cytokines expression and NF-κB pathway activation, and these changes were eliminated by SIRT1 silencing. Moreover, the role of the miR-181a-5p inhibitor on sepsis was studied in vivo. We found that the miR-181a-5p inhibitor significantly decreased the secretion of inflammatory factors, and the levels of creatine (Cr), blood urea nitrogen (BUN), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a serum for mice with sepsis. However, all the effects were reversed by SIRT1-siRNA. In summary, these results indicated that miR-181a-5p was involved in sepsis through regulating the inflammatory response by targeting SIRT1, suggesting that miR-181a-5p may be a potential target for the treatment of sepsis.

BACKGROUND: Studies evaluating the effectiveness of immune checkpoint inhibitors (ICI) for endometrial cancer (EC) are limited. This study aimed to assess the efficacy of PD-1/PD-L1 inhibitors as monotherapy for EC by conducting a meta-analysis. The predictive significance of MMR status, a biomarker for ICI response, also required further investigation. METHODS: A systematic literature search was conducted in English databases until September 2023. The analysis included objective response rate (ORR), disease control rate (DCR), adverse events (AEs), and odds ratios (OR), along with their corresponding 95% confidence intervals (CI). RESULTS: There were twelve trials totaling 685 individuals. PD-1/PD-L1 inhibitor monotherapy resulted in an ORR for 34% (95% CI = 24-44%) of the pooled EC patients. Subgroup analysis revealed a significantly higher ORR in dMMR EC (45%) compared to pMMR EC (8%), with an OR of 6.36 (95% CI = 3.64-11.13). The overall DCR was 42%, with dMMR EC at 51% and pMMR EC at 30% (OR = 2.61, 95% CI = 1.69-4.05). Grade three or higher adverse events (AEs) occurred in 15% of cases (95% CI = 9-24%) of the pooled incidence of AEs, which was 68% (95% CI = 65-72%). CONCLUSIONS: This meta-analysis provides significant evidence for the effectiveness of PD-1/PD-L1 inhibitors as monotherapy for EC. Notably, dMMR EC patients demonstrated superior treatment efficacy with PD-1/PD-L1 inhibitor immunotherapy. Further research is required to explore subclassifications of EC based on dMMR molecular subtypes, enabling improved treatment strategies and outcomes for EC patients.

Aimed at the great metallographic structure differences between every part of the large-scale thin-wall complex integral precise titanium alloy casting, a non-destructive evaluation method based on metallographic structure statistical analysis is proposed. Under the non-destructive condition, the casting skin structure information is given by means of handheld microscope. The casting skin structure statistic model is established. And the result of integral casting structure is given. Through comparative analysis between non-destructive evaluation (Method A) and metallography detection of the dissect sample (Method B), the results show that the non-destructive evaluation evaluates the metallographic structure effectively. The mean value and half-width of the grain size distribution curves fit the characteristic of Gaussian distribution. And the grain size mean value in both two methods increase linearly along with the casting thickness, and the slope deviation is within the limits of 6%; the half-width relative deviation increases exponentially along with the casting thickness, approached 26%.

Biomass burning (BB) has significant impacts on air quality, climate and human health. In China, the BB emission has changed substantially over the past decades while the multi-year variation held high uncertainty and the driving forces have addressed little attention. Here, this research aimed to conduct a comprehensive and systematic analysis of BB variation in China and provided precise and targeted BB emission reduction suggestions. The moving of high emission for BB from 2003 to 2014 was clearly identified, by the view of reliable emission estimation and anthropogenic impacts. Multiple satellite products, field survey, time varying biomass loading data and measured emission factors were adopted to better estimating BB emission and reducing the uncertainty. Social-economic analysis was added to assess the anthropogenic impacts on high emission variation quantitatively. Results showed that the cumulative BB emissions of OC, EC, CH4, NOX, NMVOC, SO2, NH3, CO, CO2, PM2.5 and PM10 during 2003-2014 were 1.6 × 104, 5.64 × 103, 3.57 × 104, 1.7 × 104, 5.44 × 104, 2.96 × 103, 6.77 × 103, 6.5 × 105, 1.15 × 107, 5.26 × 104 and 6.04 × 104 Gg, respectively. Crop straw burning (in-field and domestic) in northeast China plain (NEP), north China plain (NCP), northern arid and semiarid region and loess plateau were the key sources, averagely contributed 73% for all the pollutants emission. While domestic straw burning and firewood burning in Sichuan basin (SB), Yunnan-Guizhou plateau and southern China were main contributors, averagely accounting for 70% of all the pollutants emission. On regional level, high emissions were mainly found in SB, NCP and NEP. Temporally, high emissions were mainly found in crop sowing harvesting and heating seasons. From 2003 to 2014, the BB emission for different biomass species has changed significantly in different regions. High emission has gradually moved from SB to NCP and NEP. Firewood burning and domestic straw burning emission decreased by 47% and 14% in SB, respectively. In-field straw burning emission increased by 52% and 231% in NCP and NEP respectively and domestic straw burning emission increased by 62% in NEP. Emissions from heating season have decreased while emissions in corn harvest season were continuously increased. Analysis of Environmental kuznets curve, agricultural productivity level, human burning habits, rural energy structure and local control policies revealed the internal human driving strength of the variation for BB emission. The unbalanced development of social economy and the policy bias were primary drivers of limiting the BB management. BB emission will alleviate in NCP and aggravate in NEP. For the further emission reduction, effective measures for corn sources management, straw returning and rural energy utilization should be systematically considered. This research provides a clear evidence for the multi-year variation pattern of BB emissions, which is critical for pollution prediction, air quality modeling and targeted mitigation strategies for the key regions of China.

Progresses have been made in the development of digitalized and miniaturized rubidium atomic frequency standard (RAFS). In the traditional RAFS circuits, the 6 840 MHz microwave signal is mixed with the 5.312 5 MHz signal generated by the frequency synthesizer to obtain 6 834.687 5 MHz microwave signal, which is used to excite rubidium atom transition. Early RAFS frequency synthesizer used a large number of discrete analog devices, and showed disadvantages such as low degree of digitization, complicated parameter optimization and large physical size. The direct digital synthesizer (DDS) scheme used currently generates the 5.312 5 MHz signal directly, but often needs to multiply the 10 MHz signal. It has the disadvantages of low spectral purity and high phase noise. This paper introduces a digital frequency synthesizer solution that generates the 5.312 5 MHz signal. The design eliminates the need for a 10 MHz multiplier circuit when using a DDS device. It has the advantages of high spectral purity, low phase noise and adjustable output frequency/phase.